<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8">
<title>#inner should not be clipped</title>

<style>

body {
  margin: 0;
  background: red;
}

#perspective {
  perspective: 300px;
  perspective-origin: top left;
}

#inner {
  height: 100vh;
  transform-origin: top left;
  transform: translateZ(-300px) scale(2);
  z-index: 2;
  background: lime;
  border: 1px solid lime;
  box-sizing: border-box;
}

</style>

<div id="perspective">
  <div id="inner"></div>
</div>
